Audio frequency transformer



2,713,667 AUDI!) FREQUENCY TRANSFGRMER Application Deceniher 21, 953,Serial No. 399,551

1 Claim. (Ci. 336--'l83) This invention relates to an audio frequencytransformer primarily adapted for use in plate circuit modula tion of anappropriate radio frequency carrier. The transformer primary is adaptedto be energized from push pull amplifying means, while the secondary isadapted to be connected in the plate circuit of a modulating stage forthe purpose of modulating a suitable radio frequency carrier. inaddition, the invention is applicable to other transformers such asoutput transformers.

it is well known that capacitance between the windings of an audiotransformer and between the windings and ground affects the operation ofthe transformer. Parasitic series parallel resonant circuits aredeveloped the transformer characteristic is modified as a result. Onesolution to the problem has been provided in a previous invention by thepreser inventor described in Patent No. 2,436,738. In that case,sub-divided windings were used and the windings so connectedelectrically that capacitive efiects were concentrated and easilycompensated for. The sub-divided windings, however, introduced obviousWinding difiiculties. The present invention provides a means or"connecting standard, as opposed to subdivided, windings as animprovement over the previous invention. in addition, the leakageinductance is de creased improving the high frequency characteristic.

The drawing illustrates a transformer wound in accordance with theteachings of this invention. A shell type transformer construction isillustrated, however, the invention is equally applicable to the coretype.

The shell type transformer is indicated generally at 10. Laminations illand 12 are joined and mated in accordance with customary practice. Inaddition, the windings are assembled on the core in accordance with wellknown ractice.

The windings, as he 'nbefore stated, are all full length windings andare annularly disposed about the central lamination leg iiindings il -i,5, ii and Bi are the pri rnary windings. primary windings are wound inthe same direction. The direction of windings is indicated by the circlelocated in the center of each winding. A dot located in the circleindicates winding in one direction and a cross indicates an oppositelywound winding.

The secondary windings are indicated at l5, l7, l8, and 29. Secondarywindings l5 and 17 are wound in the same direction as the primarywindings. Secondary windings l3 and 20 are wound in the oppositedirection.

It is to be understood that the primary and secondary windings areseparated by suita le insulation 22.

With respect to the windings, it is preferable that primary windingshave the same number of turns although the number of turns may vary inaccordance with the characteristic desired.

The windings are provided with terminals hereinafter referred to asinner and outer terminals. The terms inner and outer relate the positionof the winding terosates Patent Cffice minal to the central leg 13. Theinner terminal is always at the beginning of the winding while the outerterminal is always at the end of that particular Winding.

The primary winding includes the lead wires 23 and 2 and a lead 25 fromthe center tap which is joined to a source of 15+ potential. Thesecondary winding includes the lead as from a source of 8+ potential andthe output lead 27.

The primary windings are in series relationship. A current path can betraced from the lead 23 to inner ter- .l 28, prii winding 14 to outerterminal 29. From Outer tern a1 2 to inner terminal 38, primary winding29 and outer terminal 39. Thence to inner terminal 32, primary winding16 and outer terminal 33. Thence to inner terminal 42, primary winding21, outer terminal 43 to input lead 24. Thus, the primary windings l4,l9, l6, and 21 are in series respectively.

in the secondary circuit, two parallel circuits are conn tied in series.Each parallel circuit includes two secondary windings oppositely wound.The lead 26 is connected in parallel to inner terminal 33 and outertermirial ll of windings l5 and 2% Findings 15 and 29 are, therefore, inpa allel. Outer terminal 3 inner termini-.1 4i) are ,oined to a commonlead which connects inner terminal 3 1: and outer terminal 37' inparallel. Nindings l7 and iii are therefore in parallel. Outer terminal35 and inner terminal 3d are joined in the common l l 27 which is theoutput lead. Thus, it can be seen that the oppositely wound windings 15'and 29 are connected in parallel with each other and in series with theparallel connection of windings i7 and 13. As previously indicated, eachpair oi windings in parallel in- Cll. vs one winding wound in onedirection and one winding wound in the other direction.

As a result of connecting the windings in this manner, distributivecapacitive effects are concentrated. The "zisitic resonant effects areconcentrated into two paranits so that the effects may be compensatedfor. itance between primary 21 and secondary 2i), 'een prir iandsecondary E5 is concentrated. Similarly, the ance between secondary 2i)and priinary between secondary 15 and primary 16, as well as thecapacitance etwcen primary fi and secondary E8, and primary in andsecondary 17 is concentrated and as before compensation can be had inany desired manner.

Paving described my invention, i claim:

A transformer consisting of full length primary and secondary w dingsannularly disposed the one upon the other in the allowing manner, aninnermost first primary, a r 7d secondary, a third primary, a fourthsecondary, a nun reversely wound secondary, a sixth primary, a seventhreversely wound secondary, and an eighth prin ,ry, all of said windingshaving inner and outer termitals respectively and connected as follows;the first, sixth, third and eighth primary windings are connected inseries with the outer terminals of an inner winding connected to theinner terminal of an outer winding, the second and seventh secondarywindin s connected in parallel to each other and in series with theparallel connection or the fourth. and fifth secondary windings.

References c in the file of this patent UNZTED STATES PATENTS July 19,1955 w. F. SCHMITT FLIP-FLOP CIRCUIT USING A SINGLE CORE 3 Sheets-Sheet1 Filed June 4, 1954 w M m a a 004 V- nmd a ,l mm 0 3 2 l 5 2 mm 3 MsrrE m A. \I M c 2 m 3 L) F0. 2 M T. m F W m W m W 2 .H H. a u G L 1 w r .ls w F W 4 m m Q n I w u M 1 m 1 mm. r L s+/ mm.. J a= 4 5 H M ma m 2 B0H5 mm D MSF m. m 8 U m S St W/LL/AM E SCHM/TT ATTORNEY

